title: Diel vertical migration of Arctic zooplankton during the polar night.
abstract: High-latitude environments show extreme seasonal variation in physical and biological variables. The classic paradigm of Arctic marine ecosystems holds that most biological processes slow down or cease during the polar night. One key process that is generally assumed to cease during winter is diel vertical migration (DVM) of zooplankton. DVM constitutes the largest synchronized movement of biomass on the planet, and is of paramount importance for marine ecosystem function and carbon cycling. Here we present acoustic data that demonstrate a synchronized DVM behaviour of zooplankton that continues throughout the Arctic winter, in both open and ice-covered waters. We argue that even during the polar night, DVM is regulated by diel variations in solar and lunar illumination, which are at intensities far below the threshold of human perception. We also demonstrate that winter DVM is stronger in open waters compared with ice-covered waters. This suggests that the biologically mediated vertical flux of carbon will increase if there is a continued retreat of the Arctic winter sea ice cover.
authors.affiliation: University Centre in Svalbard, Pb 156, 9171 Longyearbyen, Norway. jorgen.berge@unis.no
authors.forename: Jørgen
authors.initials: J
authors.lastname: Berge
authors.forename: Finlo
authors.initials: F
authors.lastname: Cottier
authors.forename: Kim S
authors.initials: KS
authors.lastname: Last
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Varpe
authors.forename: Eva
authors.initials: E
authors.lastname: Leu
authors.forename: Janne
authors.initials: J
authors.lastname: Søreide
authors.forename: Ketil
authors.initials: K
authors.lastname: Eiane
authors.forename: Stig
authors.initials: S
authors.lastname: Falk-Petersen
authors.forename: Kate
authors.initials: K
authors.lastname: Willis
authors.forename: Henrik
authors.initials: H
authors.lastname: Nygård
authors.forename: Daniel
authors.initials: D
authors.lastname: Vogedes
authors.forename: Colin
authors.initials: C
authors.lastname: Griffiths
authors.forename: Geir
authors.initials: G
authors.lastname: Johnsen
authors.forename: Dag
authors.initials: D
authors.lastname: Lorentzen
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Brierley
mesh_terms: D025041:Animal Migration; D000818:Animals; D001110:Arctic Regions; D002940:Circadian Rhythm; D017753:Ecosystem; D012621:Seasons; D015048:Zooplankton / Q000502:physiology*